Nothing wrong with major 7th - just about anything that has a descending run uses a major 7th in it, usually as the second chord in the sequence (eg. "C, Cmaj7, Am"). Stairway to heaven, Time in a bottle, Whiter shade of pale, etc, etc.

Where the major 7th is in the bass (eg. a bass run) then it may be labelled differently, eg. C/B. So the same bass run may be marked "C, C/B, Am".

Graham.